Production of phenol

ABSTRACT

Phenol and acetone are produced by the cleavage of cumene hydroperoxide in the presence of a solid heterogeneous catalyst with acidic activity comprising an intermediate pore size zeolite such as ZSM-5.

FIELD OF THE INVENTION

This invention relates to the production of phenol and more particularlyto a process for the production of phenol and acetone from cumenehydroperoxide.

CROSS-REFERENCE TO RELATED APPLICATIONS

Our copending U.S. patent application Ser. No. 492,093, filed May 6,1983 (concurrently with this application) describes a process for theproduction of phenol and acetone using a different catalyst (zeolitebeta).

BACKGROUND OF THE INVENTION

Phenol is an important organic chemical with a wide variety ofindustrial uses. It is used, for example, in the production of phenolicresins, this one use constituting over half the total usage,bisphenol-A, caprolactam and many other materials. A number of processesare currently in use for the production of phenol but the single processproviding the largest proportion of the total production capacity is thecumene process which now accounts for over three quarters of the totalU.S. production. The basic reaction involved in this process is thecleavage of cumene hydroperoxide into phenol and acetone:

    C.sub.6 H.sub.5.C(CH.sub.3).sub.2 OOH=C.sub.6 H.sub.5 OH+(CH.sub.3).sub.2 CO

The reaction takes place under acid conditions with the yield of bothphenol and acetone generally being 40 percent or more.

On the industrial scale, the cumene hydroperoxide is usually treatedwith dilute sulphuric acid (5 to 25 percent concentration) at atemperature of about 50° to 70° C. After the cleavage is complete, thereaction mixture is separated and the oil layer distilled to obtain thephenol and acetone together with cumene, alpha-methylstyrene,acetophenone and tars. The cumene may be recycled for conversion to thehydroperoxide and subsequent cleavage. The phenol produced in this wayis suitable for use in resins although further purification is requiredfor a pharmaceutical grade product.

Although the process described above is capable of producing both phenoland acetone in good yields, it would be desirable to find a processwhich would reduce the need for the product separation and purificationsteps which are consequent upon a homogeneous process of that kind.

The heterogenous cleavage of cumene hydroperoxide (CHP) over variousacidic solids has already been reported. For example, the use ofamorphous aluminosilicates for this purpose is described in J. MacromolSci-Chem. A5(5), 995-1005, August 1971 and U.S. Pat. No. 3,305,590describes the use of silica-alumina composites in this reaction. The useof silica-alumina gels is also described in Stud. Univ. Babes-Bolyai Ch.16(1), 61-67(1971). Other materials whose utility as catalysts for thisreaction include various zeolites such as sillimanite, as described inZh. Prikl. Khim 54, No. 8, 1793-9 (1981) and zeolites X and Y in certaincationic forms, as reported in Z. Chem. 15 Jg. (1975) 152-153 (Heft 4).The decomposition of other peroxides over zeolites X and Y is reportedin Collection Czechoslov. Chem. Commun Vol. 40, 865-874 (1975).

SUMMARY OF THE INVENTION

It has now been found that cumene hydroperoxide may be converted tophenol and acetone in good yields and with high rates of conversion andselectivity to the desired products by the use of a solid heterogenouscatalyst comprising a crystalline intermediate pore size zeolite such aszeolite ZSM-5. The yields, conversions and selectivities are generallysuperior to those produced by the use of the large pore zeolites X andY, especially with extended continuous operation. It is believed thatthis superior performance may be attributable to the greater resistanceof the selected zeolites to coke precursors which otherwise would tendto deactivate the catalyst and render it less selective.

DETAILED DESCRIPTION Feedstock

The cumene hydroperoxide starting material may be obtained in theconventional way, by oxidation of cumene in an alkaline medium, in whichthe hydroperoxide product is stable. Cumene, normally obtained by thealkylation of benzene with propylene, is usually emulsified in anaqueous alkaline solution such as sodium carbonate, at a pH of 8.5 to10.5 with an emulsifying agent such as sodium stearate. Oxidation withair or oxygen at mildly elevated temperatures of about 70° to 130° C.follows, with a final conversion of about 30 percent being common. Theunreacted cumene may be separated by distillation and recycled to givethe cumene hydroperoxide or it may be carried through the subsequentcleavage reaction and then recycled.

Catalyst

The catalyst which is used in the present process is a solid,heterogeneous catalyst which comprises a crystalline zeolite havingacidic functionality.

Many crystalline aluminosilicate zeolites are known. Some occur (atleast so far) only in nature, for instance paulingite and merlinoite;some occur only as a result of synthesis, for instance zeolites A andZSM-5; and some occur in both natural and synthetic forms, for instancemordenite, a synthetic counterpart of which is known as Zeolon, andfaujasite, synthetic counterparts of which are known as zeolites X andY. Counterparts are of course demonstrated as such by correspondence oftheir X-ray diffraction data, the indicia by means of which theindividuality of a zeolite is established. Such data are a manifestationof the particular geometry of the three-dimensional lattice, formed ofSiO₄ and AlO₄ tetrahedra crosslinked by the sharing of oxygen atoms andincluding sufficient cationic complement to balance the resultingnegative charge on the AlO₄ tetrahedra, of which a zeolite consists.

The chemical formula of a zeolite is thus

    M.sub.x/n :(AlO.sub.2).sub.x :(SiO.sub.2).sub.y

where M is a cation of valence n and x and y are the number of aluminumand silicon atoms, respectively, in the unit cell. This expression ishowever frequently transmuted into the mole ratio of oxides form,

    M.sub.x/n O:Al.sub.2 O.sub.3 :Y/.sub.2x SiO.sub.2

which is of course empirically ascertainable and thus the only formulawhich can be ascribed to a zeolite when its unit cell contents areunknown. Since the only significant quantity in such a formula is theterm y/2x, and since this term (which is almost invariably a range) canusually be satisfied by many zeolites of widely differing latticegeometry, chemical formula is not of value in establishing the identityof a zeolite. Furthermore, such a formula frequently expresses artefactwhen empirically derived, the cationic-valence-aluminum-atoms ratiodeviating from the unity which it must in fact be; and it fails toprovide for zeolites whose lattice structure can be brought intoexistence from reaction mixtures from which alumina is excluded.

The zeolite catalysts which are used in the present process enable theCHP to be cleaved to acetone and phenol at high conversions and withgood selectivity, even at high space velocities. The zeolites which areused according to the present invention are the so-called intermediatepore size zeolites, that is, zeolites which are characterized by aConstraint Index of 1 to 12 and a silica:alumina ratio of at least 12:1.

The significance of the Constraint Index of a zeolite is described in J.Catalysis 67, 218-222 (1981), together with details of the method bywhich it may be determined and examples of its value in some typicalzeolites; details of the method by which it may be determined are alsogiven in U.S. Pat. No. 4,016,218, to which reference is made for thesedetails.

Because constraint index is related to the crystalline structure of thezeolite but is nevertheless determined by means of a test which exploitsthe capacity of the zeolite to engage in a cracking reaction, that is, areaction dependent upon the possession of acidic sites and functionalityin the zeolite, the sample of zeolite used in the test should berepresentative of the zeolitic structure whose constraint index is to bedetermined and should also posses requisite acidic functionality for thetest. Acidic functionality may, of course, by varied artifices includingbase exchange, steaming or control of silica: alumina ratio.

The silica:alumina ratios referred to in this specification are thestructural or framework ratios, that is, the ratio for the SiO₄ to theAlO₄ tetrahedra which together constitute the structure of which thezeolite is composed. This ratio may vary from the silica:alumina ratiodetermined by various physical and chemical methods. For example, agross chemical analysis may include aluminum which is present in theform of cations associated with the acidic sites on the zeolite, therebygiving a low silica:alumina ratio. Similarly, if the ratio is determinedby thermogravimetric analysis (TGA) of ammonia desorption, a low ammoniatitration may be obtained if cationic aluminum prevents exchange of theammonium ions onto the acidic sites. These disparities are particularlytroublesome when certain treatments such as dealuminization methodswhich result in the presence of ionic aluminum free of the zeolitestructure are employed.

Zeolites which conform to the specified values of Constraint Index andsilica:aluumina ratio include the zeolites ZSM-5, ZSM-11, ZSM-12,ZSM-23, ZSM-35, ZSM-38, the ZSM-5/ZSM-11 intermediate, and ZSM-48 whichare described, respectively, in U.S. Pat. Nos. 3,702,886, 3,709,979,3,832,449, 4,076,842, 4,016,245, 4,046,859, 4,229,424 and 4,375,573(also U.S. application Ser. No. 303,276, filed Sept. 17, 1981), to whichreference is made for details of these zeolites. These zeolites may beproduced with differing silica:alumina ratios ranging from 12:1 upwards.They may, in fact, be produced from reaction mixtures from whichaluminum is intentionally excluded, so as to produce materials havingextremely high silica:alumina ratios which, in theory at least mayextend up to infinity. Silica:alumina ratios of at least 30:1 and higherwill be common for these zeolites, e.g. 70:1, 200:1, 500:1, 1600:1 oreven higher. Highly siliceous forms of zeolites ZSM-5, ZSM-11 and ZSM-12are described, respectively, in U.S. Pat. No. Re. 29,948 and EuropeanPatent Publication No. 14,059 to which reference is made for details ofthese zeolites.

Because the present process is acid-catalyzed, the extent of acidicactivity possessed by the catalyst will govern both the yield and thespeed of the reaction. The acidity of the zeolites may, as mentionedabove, be conveniently controlled in a number of different ways, forexample, by base exchange, by steaming or by control of thesilica:alumina ratio of the zeolite. Base exchange with alkali metalsparticularly sodium will tend to reduce the acidity of zeolites in thehydrogen form because the acidic protons become replaced with sodiumions. Conversely, alkali metal forms of the zeolite may be converted tothe more acidic hydrogen form by ammonium base exchange followed bycalcination. Either kind of exchange may, of course, be complete orpartial in order to achieve the desired variation in acid acitivity.Steaming is generally effective to reduce activity by removal of thealuminum active sites, although certain zeolites respond more to thistreatment than others. Control of silica/alumina ratio affects acidicactivity by controlling the proportion of AlO₄ tetrahedra in the zeolitewhich are available for protonation; high silica zeolites therefore tendto have lower acidic activity than those with lower silica:aluminaratios. For the purposes of the present process, it is preferred to usea catalyst with an acidity, measured by alpha value, from 5 to 1000,preferably 10 to 500. The significance of the alpha value and a methodfor its determination are described in U.S. Pat. No. 4,016,218, to whichreference is made.

The zeolite may be catalytically inactive when prepared in the presenceof organic cations, possibly because the intracrystallin free space isoccupied by organic cations from the forming solution. The zeolite maybe activated by heating in an inert atmosphere at 540° C. for one hour,for example, followed by base exchange with ammonium salts followed bycalcination at 540° C. in air. The presence of organic cations in theforming solution may not be absolutely essential to the formation of thezeolite; however, the presence of these cations does appear to favortheir formation. More generally, it is desirable to activate this typecatalyst by base exchange with ammonium salts followed by calcination inair at about 540° C. for from about 15 minutes to 24 hours.

It may be desirable to incorporate the zeolite in another materialresistant to the temperatures and other conditions employed in theprocess. Such matrix materials include synthetic or naturally occurringsubstances as well as inorganic materials such as clay, silica and/ormetal oxides. The latter may be either naturally occurring or in theform of gelatinous precipitates or gels including mixtures of silica andmetal oxides. Naturally occurring clays which can be composited with themodified zeolite include those of the montmorillonite and kaolinfamilies. Such clays can be used in the raw state as originally mined orinitially subjected to calcination, acid treatment or chemicalmodification.

The zeolite may also be composited with a porous matrix material, suchas silica-alumina, silica-magnesia, silica-zornia, silica-thoria,silica-berylia, silica-titania as well as ternary compositions, such assilica-alumina-thoria, silica-alumina-zirconia, silica-alumina-magnesiaand silica-magnesia-zirconia. The matrix may be in the form of a cogel.The relative proportions of zeolite and inorganic oxide gel matrix maytypically vary with the zeolite content ranging from 1 to 99, and moreusually from 5 to 80 percent by weight of the composite.

Reaction Conditions

The cleavage reaction may conveniently be carried out in the liquidphase at elevated temperatures, usually at a temperature from 50° C.,preferably 80° to 120° C. The reaction proceeds readily at temperatureswithin this range, without undue production of undesired by-productssuch as alpha-methylstyrene and acetophenone. However, if greateramounts of these materials can be tolerated, higher temperatures, forexample, up to 200° C. may be used although care should be taken toprevent temperature excursions caused by the exothermic nature of thereaction. Temperatures of approximately 100° C. are preferred in orderto obtain adequate reaction speed and to avoid by-product formation.

The cumene hydroperoxide is preferably dissolved in a solvent such asbenzene, toluene, acetone, cumene, or another hydrocarbon which is inertto the reaction. Alternatively, and somewhat less desirably, the cumenehydroperoxide may be suspended in an inert solvent such as an aliphatichydrocarbon or a halocarbon. The use of a solvent is particularlypreferred because intimate contact with the catalyst will be assuredand, in addition, evaporation of the solvent will assist in dissipatingthe heat of the reaction (about 60 KCal/mole). The temperature of thereaction may therefore be controlled at least to some degree bycontrolling the circulation rate of the reaction solution. A volatilesuspension medium offers similar advantages except that close contactwith the catalyst is not so readily assured.

The reaction, being a liquid phase reaction, is preferably conducted ina fixed bed or a slurry reactor. If a fixed bed is used, the exothermcan be controlled by the circulation rate over the bed, with rates of 1to 100, preferably 10 to 50 WHSV having been found suitable. It may bepreferable further to operate with a diluted catalyst, e.g. a catalystin a non-acidic, inert matrix or supported on an inert support.Alternatively, a slurry reactor may be used, with a solution of thecumene hydroperoxide flowing vertically upwards through the catalyst bedat a sufficient velocity to maintain the bed in an ebullient state. Thisform of operation will be favored because the efficient thermal transferwithin the bed promotes uniformity of conditions within the bed. Controlof the exotherm may also be effected by permitting the solvent toevaporate from the bed, after which it may be recycled.

Extremely high conversions, frequently of 100 percent, of the cumenehydroperoxide may be obtained by the present process, accompanied bygood selectivity to the desired phenol and acetone products. In thisrespect, the present process is superior to that of the known processeswhich make significant amounts of methylstyrene, acetophenone,2-phenyl-propan-2-ol and 4-cumyl phenol as by-products. In addition, theuse of a solid, heterogeneous catalyst facilitates product recovery asthere is no acid to separate from the reaction products or to dispose ofafterwards.

The invention is illustrated in the following Examples. All percentages,parts and proportions are by weight.

EXAMPLE 1

A small scale batch process was carried out by adding 0.5 g. HZSM-5(silica:alumina ratio 70, alpha value 140) to a solution of 0.375 g.cumene hydroperoxide (CHP) in 25 ml. benzene in a 100 ml round bottomflask at room temperature.

The reaction mixture was then stirred for about 3 hours after which theautocatalytic reaction appeared complete, with a final temperature of60° C. The final conversion to phenol was 100 percent by gaschromatograph.

EXAMPLES 2-4

A vertically disposed downflow reactor containing 3 ml. of the catalystbeing tested was connected for the CHP feed to be supplied at the topwith product removal at the bottom. Temperature control was arranged byexternal heating jacket with an internal temperature monitor in the bed.Product analysis was by gas chromatograph.

The feed composition is shown in Table 1 below.

                  TABLE 1                                                         ______________________________________                                        Feed Composition                                                                                Weight Percent                                              ______________________________________                                        Cumene hydroperoxide (CHP)                                                                        79.67                                                     Cumene              11.04                                                     2-Phenyl-2-propanol 6.47                                                      Acetophenone        2.56                                                      Alpha-methyl styrene                                                                              0.26                                                                          100.00                                                    ______________________________________                                    

The catalysts used were as follows:

Example 2: HZSM-5 (silica:alumina ratio 70, alpha value 140)

Example 3: Zeolite ZK-5 (alpha value 15)

Example 4: Quartz chips ("Vycor"-trademark)

The ZK-5 zeolite (small pore zeolite and the quartz chips used inExample 4 are used for purposes of comparison.

The results are shown in Tables 2 to 4 below in terms of the productdistribution, selectivity to phenol and acetone and CHP conversion aftervarying times on stream. The temperatures at these times are alsoindicated. The superiority of the ZSM-5 catalyst is apparent from thefigures for conversion and selectivity.

                                      TABLE 2                                     __________________________________________________________________________    Example 2 - HZSM-5                                                            Time (hrs.)                                                                            0.62                                                                             1.10                                                                             1.47                                                                             1.87                                                                             2.20                                                                             2.78                                                                             3.38                                                                             3.93                                                                             4.63                                                                             5.7                                       Temp (°C.)                                                                      53 58 63 70 167                                                                              167                                                                              167                                                                              152                                                                              141                                                                              141                                       __________________________________________________________________________    Product Dist.:                                                                Acetone  -- -- 1.38                                                                             6.40                                                                             16.31                                                                            14.07                                                                            15.37                                                                            16.50                                                                            23.84                                                                            28.33                                     Cumene   10.82                                                                            11.22                                                                            14.85                                                                            10.96                                                                            14.03                                                                            13.33                                                                            13.16                                                                            13.67                                                                            15.01                                                                            14.13                                     a-Methyl Styrene                                                                       1.46                                                                             1.13                                                                             1.09                                                                             0.77                                                                             25.68                                                                            28.27                                                                            27.73                                                                            26.20                                                                            28.13                                                                            14.44                                     Acetophenone                                                                           0.10                                                                             2.34                                                                             3.64                                                                             3.47                                                                             13.12                                                                            14.95                                                                            13.96                                                                            12.44                                                                            6.34                                                                             3.80                                      2-Phenyl-2-                                                                            4.89                                                                             4.01                                                                             3.65                                                                             2.78                                                                             1.35                                                                             1.47                                                                             1.35                                                                             1.40                                                                             0.67                                                                             0.55                                      Propanol                                                                      Phenol   1.34                                                                             3.79                                                                             6.42                                                                             8.52                                                                             28.15                                                                            26.59                                                                            27.32                                                                            28.80                                                                            24.94                                                                            38.61                                     CHP      81.39                                                                            77.50                                                                            68.97                                                                            67.10                                                                            0.14                                                                             -- -- -- -- --                                        Unknown  -- -- -- -- 1.22                                                                             1.31                                                                             1.11                                                                             0.98                                                                             1.08                                                                             0.14                                      Acetone:Phenol                                                                         -- -- 0.21                                                                             0.75                                                                             0.58                                                                             0.53                                                                             0.56                                                                             0.57                                                                             0.96                                                                             0.73                                      Selectivity                                                                            31.50                                                                            78.10                                                                            57.70                                                                            91.80                                                                            52.50                                                                            48.0                                                                             50.30                                                                            53.50                                                                            57.10                                                                            78.20                                     CHP Conversion                                                                         0  2.70                                                                             13.40                                                                            15.80                                                                            99.80                                                                            100                                                                              100                                                                              100                                                                              100                                                                              100                                       __________________________________________________________________________

                  TABLE 3                                                         ______________________________________                                        Example 3 - Zeolite ZK-5                                                      Temp (°C.)                                                                         80     80     80   185  191  140  130                             Time (hrs.) 1.27   2.57   2.83 3.55 3.80 4.23 4.63                            ______________________________________                                        Product Dist.:                                                                Acetone     3.76   2.46   3.42 27.49                                                                              20.75                                                                              19.56                                                                              22.92                           Cumene      16.33  13.75  16.15                                                                              15.08                                                                              12.51                                                                              11.96                                                                              12.14                           a-Methyl Styrene                                                                          1.18   0.93   1.21 19.84                                                                              26.54                                                                              24.23                                                                              18.93                           Acetophenone                                                                              2.50   2.19   3.68 3.17 8.96 14.89                                                                              9.51                            2-Phenyl-2-Propanol                                                                       7.16   5.04   6.00 0.31 0.13 0.47 0.65                            Phenol      4.68   3.65   4.25 33.75                                                                              30.26                                                                              27.90                                                                              31.59                           CHP         64.38  71.98  65.29                                                                              --   --   0.33 3.86                            Unknown     --     --     --   0.36 0.85 0.65 0.40                            Acetone:Phenol                                                                            0.80   0.67   0.80 0.81 0.69 0.70 0.73                            Selectivity 55.00  64.40  51.60                                                                              71.40                                                                              59.30                                                                              55.60                                                                              66.80                           CHP Conversion                                                                            19.20  9.70   18.00                                                                              100  100  99.60                                                                              95.20                           ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Example 4 - Quartz                                                            Temp (°C.)                                                                         76     110    198  235  235  120  121                             Time (hrs.) 0.38   0.90   1.33 4.40 4.58 5.53 5.83                            ______________________________________                                        Product Dist.:                                                                Acetone     0.08   0.08   3.47 5.73 3.28 0.21 --                              Cumene      13.69  9.64   20.30                                                                              12.71                                                                              11.72                                                                              17.48                                                                              14.39                           a-Methyl Styrene                                                                          0.52   0.25   7.16 28.55                                                                              25.47                                                                              1.15 --                              Acetophenone                                                                              2.57   2.65   21.35                                                                              30.30                                                                              43.00                                                                              3.94 3.18                            2-Phenyl-2-Propanol                                                                       7.11   6.95   20.29                                                                              8.20 7.94 8.88 8.04                            Phenol      0.06   0.38   1.57 2.92 4.66 0.53 --                              CHP         75.95  80.05  25.33                                                                              11.07                                                                              0.29 67.81                                                                              74.39                           Unknown     --     --     0.52 0.53 3.65 --   --                              Acetone:Phenol                                                                            1.33   0.21   2.21 1.96 0.70 0.40 --                              Selectivity 3.80   0.30   9.30 12.60                                                                              10.00                                                                              6.20 0                               CHP Conversion                                                                            4.60   0      68.20                                                                              86.10                                                                              99.60                                                                              14.90                                                                              6.60                            ______________________________________                                    

EXAMPLE 5

HZSM-5 (0.5 cc., silica:alumina ration 70:1, alpha=140) was mixed with 5cc quartz chips ("Vycor") and used for the cleavage of CHP in avertical, downflow reactor at a temperature of 100° C., at differentspace velocities varying from 4 to 56 LHSV.

The compositions of the feed and of the products obtained at thedifferent space velocites are shown in Table 5 below.

                  TABLE 5                                                         ______________________________________                                        CHP Conversion over HZSM-5                                                    Feed                                                                          ______________________________________                                        --    Acetone        28.3   20.1 11.5 5.5  3.2                                9.0   Cumene         12.1   12.5 12.5 12.1 14.2                               0.3   α-Methylstyrene                                                                        1.4    0.9  0.9  1.0  0.8                                2.1   Acetophenone   2.1    2.0  2.1  1.9  1.7                                6.0   2-Phenyl-2-Propanol                                                                          0.5    1.2  2.4  3.3  3.9                                --    Phenol         49.6   34.2 18.6 9.9  5.6                                82.6  CHP            6.0    29.1 52.0 66.3 70.6                                     LHSV, hr.sup.-1                                                                               4      8   15.7  38   56                                      Temperature,   100    100  100  100  100                                      °C.                                                                    Acetone/Phenol 0.57   0.59 0.62 0.57 0.56                                     CHP Conversion 92.7   64.8 37.0 19.7 14.5                                     Acetone-Phenol 94.9   93.0 88.0 80.2 60.6                                     Selectivity                                                             ______________________________________                                    

EXAMPLE 6

A sample of zeolite Y in the hydrogen from (0.5 cc) was mixed with 5 ccquartz chip ("Vycor") and used for the cleavage of CHP in a vertical,downflow reactor at a temperature of 100° C. as different spacevelocities varying from 16 to 84 LHSV.

The compositions of the feed and of the products obtained at thedifferent space velocities are shown in Table 6 below. Comparison withTable 5 shows the superior selectivity under most conditions of theZSM-5 catalyst.

                  TABLE 6                                                         ______________________________________                                        CHP Conversion over HY                                                        Feed                                                                          ______________________________________                                        -.4   Acetone        7.3    3.3    2.0  1.4                                   14.3  Cumene         18.8   18.9   15.4 14.9                                  --    α-Methylstyrene                                                                        1.1    1.0    0.2  0.2                                   1.2   Acetophenone   1.7    1.1    1.4  1.2                                   5.7   2-Phenyl-2-Propanol                                                                          3.2    4.5    5.1  5.0                                   1.6   Phenol         14.6   6.7    4.6  3.4                                   77.0  CHP            53.3   64.5   71.4 74.2                                        LHSV, hr.sup.-1                                                                               16     35     56   84                                         Temperature, °C.                                                                      100    100    100  100                                         Acetone/Phenol 0.53   0.57   0.53 0.56                                        CHP Conversion 30.8   16.2   7.3  3.6                                         Acetone-Phenol 76.5   58.8   75.4 77.8                                        Selectivity                                                             ______________________________________                                    

We claim:
 1. A process for the production of phenol and acetone whichcomprises contacting cumene hydroperoxide with a catalyst comprising acrystalline zeolite having a Constraint Index of 1 to 12 and asilica:alumina ratio of at least 12:1.
 2. A process according to claim 1in which the zeolite is at least partly in the hydrogen form.
 3. Aprocess according to claim 1 in which the zeolite is ZSM-5, ZSM-11,ZSM-23, ZSM-35 or ZSM-38.
 4. A process according to claim 1 in which thezeolite is ZSM-5.
 5. A process according to claim 4 in which the zeolitehas a silica:alumina ratio of at least 70:1.
 6. A process according toclaim 1 in which the cumene hydroperoxide is contacted with the zeoliteat a temperature of 80° C. to 200° C.
 7. A process according to claim 1in which the cumene hydroperoxide is contacted with the zeolite at atemperature of 80° C. to 120° C.